<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>事件监听</title>
</head>
<body>
        <input type="button" value="点我" id="box">
        <script>
            var box = document.getElementById('box');
            box.addEventListener('click',function (e) {
                console.log(e);             //有事件对象
                console.log(this);          //有this对象
                this.value = 'clack'

            })
        </script>
</body>
</html>